Sickle Cell : Chronic Transfusions

There may be times when sickle cell patients require a . Such situations include preparing for surgery, during pregnancy, or during a severe complication such as an aplastic crisis, splenic sequestration or acute chest syndrome. In these cases, transfusion is a one-time intervention used to reduce the severity of the complication you are experiencing.

However, if you have had a , or an MRI or TCD shows that you are at high risk for having a stroke, your hematologist may recommend you begin chronic blood transfusions.

What Does a Blood Transfusion Do? What are The Risks?

Chronic (monthly) blood transfusions have been proven to Blood transfusions are not without risks. One risk is drastically reduce a sickle cell patient’s risk of stroke. They alloimmunization, a process in which the patient receiving have also been shown to reduce the frequency, severity blood transfusions creates antibodies to certain types of and duration of other sickle cell complications. Sickle cell blood. As a result he/she may have a reaction to the blood patients usually have a hemoglobin S level of about 80- that was transfused. Alloimmunization makes it more 90%. This means 80-90% of the circulating red blood cells difficult to find blood that is a good match for the patient. are cells that can sickle and cause complications. The goal In order to prevent alloimmunization, some centers of chronic blood transfusion therapy is to bring that routinely perform RBC phenotyping (special testing for percentage down below 30%. This will mean fewer sickle antibodies) on patients so that they may cells circulating in the body, and a lower risk of give blood that is a better match for the patient. However, complications from sickling. this extended testing still does not cover all antibodies, and reactions may still occur. How is Blood Given? Another risk of transfusion is hyperhemolysis. Blood can be transfused in two ways: a simple transfusion Hyperhemolysis occurs when a patient’s body destroys or a exchange transfusion. both newly transfused cells and the patient’s own cells. In A simple transfusion involves transfusing 1-3 units of this situation, the hemoglobin level falls dramatically and blood through a peripheral IV. The transfusion takes about the patient becomes very anemic. Hyperhemolysis is rare, 3-4 hours, and must be given every 4 weeks to help bring but must be treated immediately to avoid becoming life down the hemoglobin S to target levels. Unfortunately threatening. these blood transfusions can cause iron overload. After a year, the patient must begin iron chelation therapy to prevent organ damage (see pamphlet “Iron Chelation”).

An exchange transfusion is when a special machine is used to remove the patient’s blood through an IV while For more information, contact: simultaneously infusing healthy donor blood through a second IV. A red cell exchange takes about 3-4 hours and Heather McCartney, BSN RN can bring hemoglobin S levels down to less than 10%. In Hemoglobinopathy Nurse Clinician, BC Children’s addition, red cell exchanges do not cause iron overload, so Hospital no chelation is required. However, blood work must be Office: 604-875-2345 ext 7103 done 2-3 days in advance, and IV access can be very Pager: 604-707-3895 difficult because of the size of IV required for the procedure. Email: [email protected]

Both types of transfusions have been proven to be effective at reducing the risk of stroke in sickle cell patients.

Revised May 2019